Securing Your Azure Container Deployments

This document provides comprehensive guidance on implementing robust security measures for your containerized applications on Azure.

Core Security Principles

Adhering to fundamental security principles is paramount for any cloud-native application. For Azure containers, this includes:

  • Least Privilege: Grant only the necessary permissions to users, services, and containers.
  • Defense in Depth: Implement multiple layers of security controls to protect against threats.
  • Secure by Design: Integrate security considerations from the initial stages of development and deployment.
  • Continuous Monitoring: Regularly monitor your environment for suspicious activities and vulnerabilities.
Note: Security is an ongoing process. Regularly review and update your security posture.

Container Image Security

The security of your application begins with the images you deploy. Here's how to secure them:

Image Scanning

Regularly scan your container images for known vulnerabilities (CVEs) and misconfigurations. Azure Container Registry (ACR) integrates with security scanners like Microsoft Defender for Cloud.

# Example of enabling Defender for Cloud for ACR
az acr update --name myRegistry --admin-enabled true --identity-id

Base Image Selection

Use minimal, trusted, and regularly updated base images. Avoid using images from untrusted sources. Consider using distroless or alpine-based images to reduce the attack surface.

Image Signing and Verification

Implement image signing using tools like Notary or Docker Content Trust to ensure the integrity and authenticity of your images.

Runtime Security

Protecting your containers while they are running is critical. Consider the following:

Network Policies

Azure Kubernetes Service (AKS) supports network policies to control the traffic flow between pods. This ensures that pods can only communicate with the network endpoints they absolutely need.

# Example Network Policy definition (YAML)
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: deny-all-ingress
spec:
  podSelector: {}
  policyTypes:
  - Ingress
  ingress: []

Pod Security Standards/Admission

Enforce security best practices at the Kubernetes API level. AKS supports Pod Security Standards to define and enforce security configurations for pods.

Secrets Management

Never hardcode secrets (passwords, API keys, connection strings) in your container images or application code. Use Azure Key Vault to securely store and manage secrets, and integrate it with your container orchestrator.

Tip: Use managed identities for AKS to securely authenticate with Azure Key Vault without managing credentials.

Resource Limits and Quotas

Set CPU and memory limits for your containers to prevent resource exhaustion and denial-of-service attacks.

Orchestrator Security (AKS)

Securing your AKS cluster involves several layers:

Authentication and Authorization

Leverage Azure Active Directory (now Microsoft Entra ID) integration with AKS for robust authentication and role-based access control (RBAC).

Cluster Hardening

Keep your AKS cluster updated with the latest patches and security configurations. Regularly review Kubernetes API access and node configurations.

Private Clusters

For enhanced security, consider deploying AKS as a private cluster where the Kubernetes API server is not exposed to the public internet.

Monitoring and Auditing

Continuous monitoring is key to detecting and responding to security threats:

Azure Monitor and Log Analytics

Collect and analyze logs from your AKS cluster, container instances, and other Azure services to identify suspicious activities.

Microsoft Defender for Cloud

Utilize Defender for Cloud for advanced threat detection, vulnerability management, and security posture recommendations for your container workloads.

Important: Establish clear incident response procedures for security alerts.

Further Reading